3v4l.org

run code in 300+ PHP versions simultaneously
<?php function a () { function b() { echo "I am ".__FUNCTION__."\n"; } echo "I am ".__FUNCTION__."\n"; } echo function_exists("b") ? "b is defined\n" : "b is not defined\n"; a(); echo function_exists("b") ? "b is defined\n" : "b is not defined\n"; b();
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.8 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
b is not defined I am a b is defined I am b

preferences:
267.45 ms | 405 KiB | 351 Q